The desire for small volumes of substances, individually frozen or solidified has become greater as the technology has improved and the awareness and availability of such a product has increased. This demand includes food type products, bioactive products, chemical products, and in general any liquid, semi-liquid, semisolid or solid that may be desired to be frozen or solidified in small individual units. Small individual units do not demand the thawing of a large amount of product for utilization. Measurability, novelty, convenience, reduced waste, higher quality, ease of use, flowability, handling, minimizing cellular damage, and maximizing product efficacy are also advantages that industry is discovering with small frozen or solidified units. This demand has created a need for a product that has reasonable consistency of size, shape and other physical characteristics.
In the field of bio-active products, small frozen or solidified units have significant advantages. The freezing process is very fast and results in minimal cellular and structural damage, which provides maintenance of the desired bioactive characteristics.
The rapid freezing minimizes cellular damage caused by the formation of ice crystals, normally associated with freezing. Bioactive products are often freeze dried for storage. The characteristics of the units make them excellent for freeze drying. The more consistent the size and form of the units, the more favorable they are for a freeze drying process.
One of the advantages of a small volume of frozen or solidified product is that it can be made to flow like ball bearings (flowability). Thus, the handling of specific amounts of units that may vary with demand is possible. Agglomeration and deformed individual units inhibit the ability to flow as desired.
Measurement and utilization is also an important feature. If an average weight of the product is known, a specific amount can be utilized without thawing a larger block of product. The thawing of the desired amount of product is faster as a direct result of the relatively large surface area per unit of weight as compared to a frozen block of product. Many characteristics are improved significantly as a result of the rapid freezing or solidification of the small volume of liquids.
There is prior art in the field of production of frozen units by utilizing a cryogenic liquid. Much of the known art utilizes a particular cryogenic liquid, such as Liquid Nitrogen (LN2).
The main problem with the prior art is that the small volumes of substance are introduced into the cryogen with relatively little consideration of the manipulation and management of the cryogen itself. This results in the formation of random or poorly formed units. Creation of deformed units is commonly referred to as the “popcorn” effect. The units look like “popcorn” rather than smooth spheres.
Consistency of size, structure, texture and surface quality as well as control of agglomeration has not been able to be a manageable and controllable feature previously. All of these variances result from the inability to control and manage the rapid heat transfer that occurs in the process. This rapid heat transfer results in remarkably violent gasification, which results from introduction of a relatively warm substance into the extremely cold cryogen. Gasification occurs at the interface between the cryogen and the forming units. Violent gasification results in cavitations at the surface of the cryogen resulting from the creation of gas bubbles, which can break the surface of the cryogen. Gas bubbles bursting at the surface of the cryogen can lead to incomplete and non-uniform immersion of the introduced substance into the cryogen. It also causes the units to violently interact. This violent interaction results in significant structural alterations of the units.
Agglomeration is also often a problem as the rapidly forming units often combine with other units resulting in multiple units combining and solidifying together. This agglomeration affects the flowability of the product as well as affecting other desired qualities
The relevant prior art is referenced as follows:
Canadian Patent #937450:
This patent describes the deformation that would naturally occur when a small volume of liquid is entered into a body of cryogenic material.
Canadian Patent #964921:
This art describes a small volume of liquid being introduced into an unmanaged and static body of cryogenic liquid.
Canadian Patent #1217351 and U.S. Pat. No. 4,655,047:
This patent describes the improved formation frozen pellets. This patent describes the introduced liquid relative to speed into the body of cryogenic liquid.
Canadian Patent #2013094 and U.S. Pat. No. 4,982,577:
This patent identifies the previous patents' lack of ability to control the exposure of the cryogenic liquid to external heat sources and thereby the subsequent waste of the cryogenic liquid. Although it establishes a good method of handling the liquid for the purposes of cost, it does not identify, mention or claim the benefits of a process of manipulation of the fluid dynamics of the cryogenic liquid to produce the ability to manage the characteristics of the introduced liquid as it solidifies.
U.S. Pat. No. 4,687,672:
This patent describes a freezing of large volume of product and its subsequent fracturing and grinding to produce a granular product.
U.S. Pat. No. 5,126,156:
This art describes a liquid being introduced into a cryogenic liquid without any reference to manipulation or management of the cryogenic liquid only referring to the removal of the pellets from the liquid after freezing and a screening process to extract only the pellets from the liquid via an auger in a similar fashion to Canadian patent 964921.
U.S. Pat. No. 6,000,229:
The art is basically a tub of cryogen with an introduction point of cryogen. In addition an auger for the removal of solidified pellets. There is not any attempt to manage the heat transfer, gasification or other destructive aspects.
Generally, the prior art in the field focuses on the actual small volume of liquid being introduced and the handling and removal of subsequently-frozen product from the liquid cryogen. The prior art typically does not identify or discuss what actually occurs within the body of the cryogen or any methods or apparatus for managing the heat transfer and gasification that directly affects the structure and formation of the pellet being produced.